HISPANIOLAN AND BAHAMAN ANNULARIIDAE 251 



U.S.N.M. No. 391757 contains 137 specimens collected by Bartsch 

 on Western Plana Island. 



COLONEL,I>A ACKLINSENSIS, new species 



Plate 38, Figure 8 



Shell small, almost cylindroconic. Nuclear whorls 2, well rounded, 

 smooth, forming a slightly mammillated apex. Postnuclear whorls with 

 strongly constricted suture, which gives them a rather rounded aspect. 

 The postnuclear whorls are crossed by rather closely spaced, moderately 

 elevated axial riblets, which vary somewhat in strength and also in 

 spacing. Some of these axial riblets become expanded at the summit into 

 a hollow denticle. Periphery strongly rounded. Base narrowly openly 

 umbilicated, marked by a continuation of the axial ribs which extend 

 over the umbilical wall, which also shows an indication of several ob- 

 solete spiral threads. Last whorl solute for a fifth of a turn. Aperture 

 subcircular; peristome double, the inner slightly reflected; the outer 

 moderately broadly expanded, widest at the posterior angle, a little nar- 

 rower on the rest of the outer, basal and columellar lip, narrowest on 

 the parietal wall. Operculum typically colonellid. 



The type (U.S.N.M. No. 536843) was collected by Bartsch at Pinnacle 

 Point, Acklins Island. It has 3.3 whorls remaining and measures: 

 Length, 8.2 mm.; greater diameter, 3.7 mm. 



U.S.N.M. No. 392229 contains 9 topotypes from the same source. 



U.S.N.M. No. 393339 contains i specimen collected by Bartsch from 

 the hill inland from Cornucopia, Acklins Island. 



This species is easily distinguished from Colonina mariguanensis by 

 having the denticles at the summit produced by a mere expansion of 

 single ribs. In C. mariguanensis they are the fusion product of several 

 riblets. Both of these species have the last whorl solute; in C. wai- 

 ling ensis the last whorl is not solute. 



COt,ONELL,A WATLINGENSIS (Ball) 



Shell small, almost cylindroconic, varying from flesh-color to chestnut- 

 brown, unicolor, or variously banded ; peristome always pale, even in the 

 darkest specimens. Nuclear whorls 2, well rounded, smooth, forming a 

 rather conspicuous apex. Postnuclear whorls moderately strongly 

 rounded, marked by retractively slanting axial riblets, some of which 

 become expanded into hollow cusps at the summit, or else two or more 

 may fuse to form a hollow cusp. The spiral sculpture consists of rather 

 distantly spaced, not very strongly developed, low, broad threads, which 

 give to the axial riblets a slightly wavy outline and feeble tuberculation. 

 Suture well constricted. Periphery well rounded. Base moderately long, 

 well rounded, narrowly openly umbilicated, marked by the continuation 

 of the axial riblets and spiral threads of about the same strength as 

 those on the spire. These spiral threads also render the axial riblets 

 nodulose, the nodules being a little stronger on the base than on the 



